power system overvoltages due to switching, lightning and other disturbances are the main problem for designers of the power transformers. once some frequencies of the incoming surges match with some of the natural frequencies of transformer winding, the resonance phenomenon is expected in transformer winding. the resonant overvoltages may destroy the insulation between turns and cause to insul...

Transformers are one of the most critical and essential components of electricity transmission and distribution. The life of a transformer is determined by the life of its paper insulation and transformer oil. To maximize the lifetime and efficiency of transformers, it is essential to be aware of possible faults that may occur and to know how to prevent them. One of the major faults in transfor...

Power system overvoltages due to switching, lightning and other disturbances are the main problem for designers of the power transformers. Once some frequencies of the incoming surges match with some of the natural frequencies of transformer winding, the resonance phenomenon is expected in transformer winding. The resonant overvoltages may destroy the insulation between turns and cause to insul...

The development of the transformer insulation failure undergoes three stages: insulation aging, incipient faults and a short circuit. This paper presents a complete scheme to simulate single-phase transformers with insulation deterioration and arcing phenomena i.e. in the first two stages. The approach incorporates Transmission Line Methods (TLM), Jiles-Atherton Hysteretic Model, Composite Cass...

The development of the transformer insulation failure undergoes three stages: insulation aging, incipient faults and a short circuit. This paper presents a complete scheme to simulate single-phase transformers with insulation deterioration and arcing phenomena i.e. in the first two stages. The approach incorporates Transmission Line Methods (TLM), Jiles-Atherton Hysteretic Model, Composite Cass...

In this paper, the properties of the physical and chemical materials, such as low loss amorphous HB1 core, high temperature resistance winding and insulation vegetable oil have been developed for use in liquid-immersed power transformer. The measured results of magnetic properties with different ferromagnetic materials core were obtained. Considering winding property for operation above 95°C co...

Power system overvoltages due to switching, lightning and other disturbances are the main problem for designers of the power transformers. Once some frequencies of the incoming surges match with some of the natural frequencies of transformer winding, the resonance phenomenon is expected in transformer winding. The resonant overvoltages may destroy the insulation between turns and cause to insul...

Power transformers use Kraft paper as insulation in the electrical windings present in the core, which is immersed in oil. In service, the temperature of the windings of core will go to 75C to 85C. If the transformer is over loaded, then the temperature can exceed upto 100°C causing the cellulose chains in the paper to cleave at an accelerated rate, which results in the degradation of mechanica...

Polarization-depolarization current (PDC) measurements are now being used as a diagnosis tool to predict the ageing condition of transformer oil-paper insulation. Unfortunately, it is somewhat difficult to obtain the ageing condition of transformer cellulose insulation using the PDC technique due to the variation in transformer insulation geometry. In this literature, to quantify the ageing con...

This paper presents an experimental investigation of transformer dielectric response and solid insulation water content. The dielectric response was carried out on the base of Hybrid Frequency Dielectric Spectroscopy and Polarization Current measurements method (FDS &PC). The calculation of the water content in paper is based on the water content in oil and the obtained equilibrium curves. A re...